Changelog for Elixir v1.21

v1.21.0-dev

1. Enhancements

EEx

• [EEx] Support splitting middle expressions across EEx clauses

Elixir

• [Access] Add support for keyword lists in Access.key/2 and Access.key!/1
• [Code] Add support for the :erlc_options compiler option
• [Code.Formatter] Add a :migrate_atom_interpolations option
• [Kernel] Improve performance of type constructors and complex intersections
• [Kernel] Warn on binary patterns with segments that are not byte-aligned
• [Kernel.ParallelCompiler] Add a hint when spawned processes cannot load modules defined during compilation
• [Keyword] Optimize Keyword.pop/3, Keyword.pop!/2, and Keyword.pop_lazy/3
• [List] Add List.to_existing_atom/2 and List.to_unsafe_atom/1
• [MapSet] Optimize MapSet.symmetric_difference/2 when set sizes differ
• [Registry] Optimize exact key matching in lookups
• [String] Optimize String.bag_distance/2
• [String] Add String.to_existing_atom/2 and String.to_unsafe_atom/1
• [URI] Optimize percent-decoding and URI.to_string/1

ExUnit

• [ExUnit.Assertions] Add trace/3 helper

2. Bug fixes

Elixir

• [Calendar] Fix Calendar.strftime/3 formatting of negative years with %y
• [Calendar] Fix rounding for :day, :hour, and :minute units in DateTime.diff/3, NaiveDateTime.diff/3, and Time.diff/3
• [Calendar.ISO] Fix Calendar.ISO.valid_time?/4 to reject non-integer microsecond precision
• [Calendar.ISO] Reject negative zero UTC offsets in basic formats
• [Code.Fragment] Fix cursor completion when operator keywords such as in, when, and, or, and not follow another operator
• [Date.Range] Fix slicing date ranges with stepped ranges
• [Duration] Reject duplicate seconds in Duration.from_iso8601/1
• [Enum] Fix Enum.min/2,3 and Enum.max/2,3 with custom sorters on ranges
• [IO.ANSI.Docs] Recognize additional punctuation delimiters when rendering Markdown
• [Kernel] Fix expansion of rebound variables in bitstring size expressions
• [Kernel] Expand defguard macros separately in guard and body contexts, preserving and/or error semantics outside guards
• [Kernel] Fix map field type inference in the presence of empty map types
• [Kernel] Fix tuple fetch and deletion type operations across equivalent tuple types
• [Kernel] Fix variables defined in one default argument leaking into subsequent default arguments
• [Kernel.Typespec] Preserve metadata when proxying to Elixir typespecs
• [Keyword] Delete duplicate keys when Keyword.get_and_update/3 and Keyword.get_and_update!/3 return :pop
• [NaiveDateTime] Fix NaiveDateTime.diff/3 over-counting incomplete units
• [Range] Fix Range.disjoint?/2 for single-element ranges with a negative step
• [String] Fix String.reverse/1 grapheme ordering around invalid UTF-8 bytes
• [String] Return 1.0 from String.bag_distance/2 for two empty strings

ExUnit

• [ExUnit.Assertions] Fix refute_in_delta/4 at the delta boundary and with negative deltas
• [ExUnit.CaptureIO] Stop StringIO processes when capturing a named device fails

IEx

• [IEx.Autocomplete] Fix completion crashes on maps with non-atom keys
• [IEx.Evaluator] Recognize ** and not in as continuation operators
• [IEx.Helpers] Fix r/1 when multiple modules are defined in the same file
• [IEx.Helpers] Fix heap and stack memory calculations in process_info/1

Mix

• [Mix.Release] Accept chardata paths in Mix.Release.make_boot_script/4
• [Mix.SCM.Git] Raise if Git refspecs start with -
• [mix deps] Recompile path and fetchable dependencies when one of the dependencies they were compiled with is removed
• [mix deps] Mark fetchable dependencies for compilation when their build exists but their SCM manifest is missing
• [mix deps.compile] Preserve code paths and compiler options across OS partitions
• [mix format] Pass :sigils to plugins invoked for sigils, allowing nested sigils to be formatted
• [mix new] Avoid trailing whitespace in generated files

3. Hard deprecations

Elixir

• [Macro.Env] Macro.Env.fetch_alias/2 and Macro.Env.fetch_macro_alias/2 are deprecated, use Macro.Env.expand_alias/4 instead

4. Soft deprecations

Elixir

• [Kernel] Atom interpolation (:"foo_#{bar}") is deprecated in favor of explicit String.to_unsafe_atom/1
• [List] List.to_atom/1 is deprecated in favor of List.to_unsafe_atom/1
• [String] String.to_atom/1 is deprecated in favor of String.to_unsafe_atom/1

v1.20

The CHANGELOG for v1.20 releases can be found in the v1.20 branch.